The objective of this study is to improve knowledge and understanding of disparities in drug use and related attitudes, perceptions, and behaviors concerning drug use and drug treatment utilization among Hispanic and non Hispanic populations living in proximity to the U.S./Mexico border. This is a geographic area in which the mainstream culture is heavily bicultural, a pattern which is expected to typify an increasingly large segment of the West and Southwest regions of the United States during the next decade. Knowledge gained in this study is expected to benefit service planners who would anticipate need for current and future service strategies to better respond to the problems and needs of Hispanic and bicultural populations. Specific aims are 1) to describe the prevalence of substance use, abuse, and dependence, and the demographic and social correlates of use among households living on the border, and to measure the changes in prevalence that have occurred during the past six years since a similar study was done; 2) to investigate the role of acculturation in explaining differences in substance use within the Hispanic border community; and 3) to determine border residents' attitudes and behaviors related to the utilization of treatment services and the correlates of these attitudes and behaviors. These questions will be addressed through an in-person survey of 1200 adults living in households: 400 from the El Paso metropolitan area, 400 from the Rio Grande Valley metropolitan area, and 400 from colonias (rural, unincorporated communities often characterized by lack of basic public services).